Process and apparatus for producing direct currents having limited strength.



- M. M. osnos: PROCESS AND APPARATUS FOR PRODUCING DIRECT .GURRENTS HAVING LIMITED STRENGTH APPLIOATIOITIILED 001. 29,1907. i 93 1,336. Patented Aug. 17. 1909.

A M. M. OSNOS. Y 4 PROCESS AND APPARATUS FOR PRODUCING DIREGT GUREENTS HAVING LIMITED STRENGTH. Y r I v APPLICATION FILED OUT. 29,1901. I 931,336. I Patented Aug. 17, 1909.

2 SHEETS-SHEET'Q D STATES PATENT OFFICE.

nnmnsn canoe, or rRnNnron'r-oN-rnn-MAIN, GERMANY, Assienos 'ro FIRM or FELTEN & GUILLEAUME-LAHMEYERWERKE ACTIEN-GESELESOEAFT, or FRANK- FORT-ON-THE-MAIN, GERllrLAiNY.

nnocnss mm arr murderer. rnon crcme mnne'r commute navme Lmr'mn s'rnnno'rn.

Bpeci-flcafiqn of Letters resent.

Application mes October 29, 1907. semi No. 899,684.

4 'sias, and a resident of Frankfort-on-thei Main, Germany, have invented certain new and useful Improvements in a Process of and .ifipparatus for Producing- D-irect Currents aving a Limited Strengt of which the fol-. lowing is a specification; I

My invention relates'to improvements in systems for controlling the strength of the current su plied by direct current d'ynamos, and the o'jtect of the improvements is to provide "a system, whereby the current is el'd within certain limits, though the resistance or the counter electromotive force of the circuit is considerably varied.

The system is particularly useful in (1 namos supplying current to -circuits whic include apparatus consuming direct current, the strength of which varies within lfar e limits, or to circuits the resistance of whic 1,- or the counter-electromotive forces of which vary within large limits, or are intentionally varied. For example, search lights are operatedin such a Way'asjto start the are lamps of the same by separating the carbons, while they are cut out by bringing the'said carbons in contact with'each other. Now, if in such cases each arc lamp is provided with a dynamo of its own, as is usual, the said dynamo will be short-circuited when switching out the lamp. Therefore, a dynamo designed for such purposes must be constructed in such a way, as to permit a considerable decrease of the resistance of the circuit,'or a short-circuiting. For this purpose, it has been suggested to counter-compound the dynamo by means of a field electromagnet energizedby theworking current, which means, however, have not proved suflicient to meet practical requirements. By the said means the current can be held below a certain limit in case of'a short-circuit. But the-strength of the current in case of a short-circuit is about'double' the maximum current supplied by the machine under normal conditions.

be-overloade in case of a short-circuit."*

however the machine is operated in sucligtway as to have its maximum current in casev r of a shortecircuit, it would not be operated Q at its'full capacity under conditions.

v If thereforethe machine is normally operated at its full load, it would" v Now, my invention consists in providingmeans, whereby the dynamo may be oper ated at its full capacity and atthe same time avoiding an excessive increase of the current in case of a short-circuit. I

For this purpose my invention consists in preventing an lncrea'se ofthe current, in case MM Au 1-7, L909. 7 r

of a decrease of theresistance of the circuit,

by causing the working current to roduce a magnetic field and by generating y means in i of said field, an electromotive force which 0 rates to weaken the main field of the a; -0 e, when the current of the machine is in creased. The said weakening effect can take place by energizing, by means of the; field manet located in line with the main current due to said electromotiye force, a

field, or y the said electremotive force in t e energizing circuit of the mainf field magnet.

For the purposeiof explaining the inven tion,-I have shown several examples of syn;

tems embodying. the same in the accompanying drawings, in which the same letters reference have been used in all the figures to; indicate, corresponding parts.

Inthe said drawings, Figure 1 is a diagrammatic view of a system embodying the invention, :and' Figs. 2' ,to 7 are diagram-I. matic views of various systems embodying modifications of the system shown in Fig. I, the various figures showing means for 0011 .necting the electro-ma-gnets in diilerent ways. j In the example shown in Fig. 1, a shunt wound dynamo is illustrated which comprises two field magnets f, f, and working. or main brushes 0, 0, arranged in a line substantiall at right a les tothe axis of the main fie d magnets f. By means of an overcompensati coil 0, the' field set up in the armature in t e directionof the brushes 0, a, is more than balanced, so that a field is' working current, tweenf field m" ets I providesubsidiary brushes If, cofiperating with the field set up in the direction the main brushes, to generate an electro tion of the -armature 1n {the overcompens'iiin;

ive force by the rota-1 I ing field which. counteracts the v energizing current of the c il a.

: From the fastener l same way the field produced by the winding i 5133 will be sufiicient.

' Current-may fall to zero, if'the resistance of that the machine may be said tdhconsist of two systems, that is of asystem which comprises the field winding f, f and the brushes a, a, and a second system which comprises 6 the windin .c and the brushes 1), b. Evi dently the 'eld of the first system, which is l produced by the windings f,f, does not pro- I I duce, in a practical sense, an. electroinotive l force at the brushes 6, b. of the second sysl ld-tem, because the brushes'b, b are located in the neutral zone of the field f, f. In the 0 cannot direct] produce an electromotive force at the brushes a, a. If the working current taken from the brushesa, a,'is increased by a decrease in the resistance of the line, as by cutting out a lamp, thereby strengthening the field c, the electromotive force between the brushes b, b, is increased, and the voltage of the working current which, in theexam'ple shown, includes arc lam s is decreased. This decrease of the v0 tage, however, causes a decrease of the field energizing voltage, and thereby also a' weakening of the current exciting the main field, and the increasiny electromotive force between the brushes 6, h

ounteracting said energizing voltage produces a further decrease of the energizing current, so that the main field cooperating with the brushes a, a, is weakened; and therei fore the current tal en from the brushes a, a,

, remains substantial y constant.

To produce a sufiicient effect on the ma chine an overcompens ation of the field in 'the direction of the main brushes amounting Under certain circumstances, for the purpose of adjusting the. automatic regulation. of the machine the field operating in the direction of the brushes (1 may be influenced 'by a shunt coil 9, operating in the direction of the field set up in the armature and opposite to the field produced by the compensate. ing coil 0. Instead of providing a special COIl g the brushes (1, a, may be displaced from the axis vertical to the axis of the main field of the machine, which displacement, however, musttake place in a direction oposite to the usual displacement of the )rushes of dynamos, that is, in a direction opposite to that of the .revolution of the ma-- chine. As it is known in the art, by prop erly displacing the brushes of a direct current dynamo, the armature field can ,"bc compensated to a greater or less degree.

If required, the machine may be provided with a special field coil apart from the shunt.

' coil f, a coil (1 being shown in the example 60 illustrated in Fig. 1. By means of the saidcoil the machine receives a certainconstant pressure, whereby any considerable decrease of the currentbelow the normal is avoided. Where'only a shunt; coil is provided, the;

the circuit is very small. If on the contrary,

the field is produced merely by means of a separately energized coil, the current in case. of a short-circuit, is too large. using the modification just described, under But when any circumstances a. practically constant practically construct the coil 0, that a part only of the armature field is compensated by the same. In

this case, in addition to the coil 0, the coil 9 is so arranged as to act in the opposite direction to that previously described, that is, in the same direction as c and its dimension is such, that under normal conditions, the sum of the fields produced by the coil 0 and by the coil 9 are stronger than the armature field produced in the direction of the brushes (1, a. If new the current is increased a certain amount, on account of a decrease of the outer resistance ofthe working circuit, the difference between the field of the coils, depending upon the load of the machine, and. the field of the coil 9, is increased. Thereby the main field in the direction of the line b, b, I

is weakened, so that the voltage and the excitation of the shunt coil are decreased. ,To illustrate the invention more clearly, an

example illustrating the effect of the various coils will now be given. If the dimension of, and the current passing through the coil 9 correspond to ampere turns, and the overcompe nsating field produced by the difference between the fieldv set up in the armature and theficld set up the coil 0 corresponds to 90 ampere turns-,the sum of both is 10 ampere turns, whereby the field is strengthened. If new the overcompensating-field be increased 5% that is to 94.5 ampere turns,

"the sum of the fieldsis 5.5 ampere, turns.

The field is, therefore, weakened but its di rection is not altered.

In Fig. 2, the connections of the brushes b, b, to the field magnets have been changed as compared with the example shown in Fig.

1. Now, as the field of g is opposite to the" armature field, the brushes may be displaced relatively to the coils h or g'and out of the neutral zone inv the usualmanner, that is in the same directionsas in'a dynamo,- while in the exampleshown in Fig. 1 the said dis.- placemont must be'eli'ected in the opposite direction. In. this modification coils g and c act in the same direction to overcompensate the armature cross-field.

The field it is separately excited, thereby accomplishing the same result obtainedin Fig. 1 by the use of an auxiliary field d. The coil 9 which assists tsetseenergizing said coil, the machines illustrated being in addition provided with shunt wound magnets,

oyercotnpensate the Furthermore, it may a furtheradditiona field magnets, separately energized field and compensating means. Inall these modifications the coils g and c together be advisable to rovide coil is connecte to the subsidiary brushes 5, b, as shown iniFig, 5, y

:Intth'e example shown in Fig. 3, the magthe armature field is 'energized from a battery e, the additional mags listg counteractin "nets it being connectedto thei'workmg cir- By separately excithig-the fie means a turns remain constantand therefore" 0 1d 9 by attery or the like the-amlpere' oser ulationmay be obtained. p I ig. 4 shows'an example inwhich the creasss a strong field is selt up-in opposition to the field h.

A further example is shown in Fig. 5 in which the magnet g is arranged as in the example shown in Fig. 2, the electromagnet It being separately energized from the battery 6 and-a s ecial additional coil 76 connected to the su sidiary brushes b, b, being proided in the same axiswith the coil h. By providing a field winding h which is separatelyexcited, the same results and advantages are obtained as were obtained in the modification shown in Fig. 1 by the winding (1.

Fig; 6 shows a modification of the arrangement shown in Fig. 3, the electromagnet It being connected to the working circuit, while I the coil k, as in theexample shown in Fig. 5,

. is connected to the subsidiary brushes.

, By omittin As appears from Fig. 7 it may be preferable, under certain circumstances, to omit the shunt clectromagnet h shown in Fig. 6.

this shunt magnet h the regulation of t lekmachine 1S dependent altogether upon the actionof the auxiliary 'coil 7c.

In all the examplesflbowever, which show different forms of my invention. the electromotive force which acts on the main exciting field so as'to decrease the same when the strength of the current is increased, is produced by the rotation of the armature; the

.field required in all the cases is producedby "the simultaneous efi'ect of a compensating coil energized by the working current, and of an exciting coil energized by the machine itself, or by a separatesource of electricity the field of the'said coils operating 1n the same direction.

I, claim In a system forprpducing curarmature cross-fields.

magnet is energized from the subsidiary. brus chinbifiation rent of limited strength, the

oi ineiins fdr with a direct current dynamo, setting up the direction of the working brushes of the .d amo and dependent upon the strength 0 the working current supp ied by the same, means for causing the electromotive force produced in the armature by said subsidiary eld to weaken the main field upon an in crease of the working current and an auxiliary field for the-subsidiary 'field, excited by a current se arate from that; generated by the subsidiary field. I

2. In a systeni for producing direct current of limited strength, the combination with a direct current dynamo, of means for setting 11 a subsidiary magnetic field passing t rough the armature direction of the working brushes of the dy-' name and dependent upon the strength of the working current supplied by the same, means for eausingthe electrornotive force reduced 'inthe armatureby said subsidiary eld to reduce the electromotive force .excit-- ing the main field upon an increase of the working current and an auxiliary field for the subsidiary piatlzca1 from that generated bythe subsidiary e I V -3 In a system for producing direct current of limited strength, the combination with a direct current dynamo, of means-for setting u st'antially in alinement with the working brushes of the dynamo" and dependent upon the strength of the Working current, subsidiary brushes bearing upon the armature and connected in series with the exciting winding of' the main field magnet, said brushes cooperating with the subsidiary magnetic field to acting to wea en the main field upon an increase of the Working cpricnt and an auxil iary field for the subsidiary field, excited by a current separate from that generated by the subsidiary field.

4. In a system for prioducing direct current of" limited strength, the combination with a direct current dynamo, of means for setting up a subsidiary magnetic field, substantially in alinement with the working brushes of the dynamo and'dependent upon the strength of the Working current, subsidiary brushes bearing upon the armature a subsidiary magnetic field ass 'ing through the armature substantia yin substantially in the a subsidiary magnetic field subproduce an electrometive force:

and connected in series betweentwo sections rent and an auxiliary field for the subsidiary .field, excited by a current separate from that generated by the subsidiary field.

' 5,;In a system for producing direct our-- electroinotive force produced in the armature by said overconipensating coil opposes the flow of current in the main field upon an iiierease of the working current.

6. In a system for producing direct current of limited strength, the combination \vith a direct current dynamo, of means for setting up a subsidiary magnetic field passing through the armature substantially in the direction of the working brushes of" the dynamo and dependentupon the strength of the current supplied by the same, means for causing the clectromotive force produced in the armature by said subsidiary field to weaken the main field upon an increase of the working current, and an additional field exciting coil adapted to prevent the ,main

'field from falling below a certain limit.

7. In a system for producing direct 'current of limited strength, the combination with a direct current dynamo, of ineansior' setting up a subsidiary magnetic field passing:

through the armature substantially in the direction of the working brushes of the dynamo and dependent upon the strength of the current sup died by. the same, a separately excited-he d magnet acting in a direction op osite to said subsidiary field, and means for causing tbe electromotive torce produced in the armature by the combined action of said subsidiary field and separately excited '[icld to weaken the main 'licld upon an increase oi the working current.

. 8; In a system for producing direct current of limited strength, the combination with a direct current dynamo, of means for setting u a subsidiary magnetic field along the line or the 'rmature cross field and dependent upon the strength of the Working current supplied to the-same, means for causing the elect rongctivc'force produced in l the armature by said subsidiary field to,

Weaken the main field, and an auxiliary field 'l'or the subsidiary .iield excited by a current separate irom that generated by the subsid iary field. 9. In a system oi producing direct current of limited strength, the combination with a direct current dynamo, a subsidiary winding in the main circuit for setting up a subsidiary field along the line of the armature cro'ss field and dependent upon the strength of the Working current, means for-causing the electroinotive force produced in the armature by said subsidiary field to Weaken the main field, and anauxiliary field for the subsidiary i l l r field excited by a current separate froni'that "generated by the subsidiary'field.

10. In a system for producing direct cur 1 rent of limited strength, the combination with a-direct current dynamo, a subsid ary winding in the main circuit for settingupa subsidiary field along the line of the arma-q ture cross field and-dependent upon the I strength of the working curi'ent,'i'neans for causing the electromotive force-produced the armature by saidsubsidiary field to 011-;

pose the electroniotive'force applied to the;

main field, and a regulating winding .for; the

subsidiary winding excited by a current sepa- 7 5 rate from that generated by 'the subsidiary rent of limited strengtln: the coinbination1 with a direct current dynamo, a subsidiary circuit, said windings having/their polar axes along the :line' connecting the working V brushes, and means for'causing the electro l 355% motive force, producedfin the armaturebyP I said subsidiary field to oppose the electro-j. f

motive force applied to the main field. f

12. In a system for producing direct eur-y' rent of limited strength, the ,combinationec" 1 with adirectcurrent dynani0,of aseries field winding in the maincircuit, a shunt winding z 0' connectedv across the main circuit, said Wiii'd ings having their polar axes along the line connecting't-l e Vv'Ol l 1Dg= brushes, and said shunt Winding being opposed to said series winding, and means for causing. theelectro-Q motive'forec produced-in the armaturej-byt said se'riesfwinding to oppose the elect romo- 1 cur i I acid of limited strength, the combination tive force applied to the main field:

13. In a system for producing direct with a direct currentdynaino,of a series field winding in the main circuit, a shunt Winding connected across the main circuit,-sa'-id windings having their polar'axes alongtheline (-onncctiug the working brushes, "ands Y shunt winding being opposed to said series winding, means lo-r causing thee'lectromotive 'l'erce produced in the arn aturesby said series winding to oppose theeleetroinotive. 1"

force applied to the main field, and an additional held winding adapted to prevent the i In testimony whereof I have signed. my 11 5 name to this specificat on in the'pr esence main. field from. 'l'ai ling below a certain limit. 

